Visa and the Romanian Banks Association have reported notifications of a possible database security breach at a European processor.
According to Romania Business, CEC Bank blocked 17,000 cards on suspicions of a security breach shortly after Visa was notified.
Visa's Romanian office was reportedly working with banks to protect cardholders and asked customers to report suspect activity.
The Romanian Banks Association said on 14 December it was notified of a security breach at a European processor that might have led to the theft of transactional data.
“The bank has been informed that a number of cards issued by banks in Romania and abroad have been potentially compromised through an international database," CEC Bank said in a statement.
The bank blocked "a number of cards" and reissued PINs.
However, it added that the attack did not target CEC Bank's cards specifically and was not due to a vulnerability within the bank.
So far, CEC Bank is the only bank in Romania to have declared itself a victim of the breach.
The Heartland Payment Systems breach in January 2009 led to the compromise of 130 million credit cards after intruders broke into the systems and planted malicious software to steal card data carried on the company's networks.